Got inspired by Mr Dawber and his home made trolley on YouTube.
He is a brilliant guy and knows his trade very well.

I have tweaked his trolley a bit to accommodate my needs.
I've attached a hose reel from screwfix (£15) and 30 meters of hose (Gardiner currently £4.50) to the trolley. Also added a flow controller and a wireless switch that works great even around corners. To improve stability I put a bolt through to keep the load plate in one position. The wheels had to be put closer together cos it wouldn't fit in my small car. Also the handle bar had to be lowered.

The box is placed by the handle bar for convenience plus I didn't want any water to spill on the electrics.
Thanks to the reel that swivel I don't need to take the trolley out of the car when doing a small job.
For bigger jobs I got another reel with 100m hose that can attach to the pump on the trolley in a second.

I though that I share this with people who have started recently and looking for a cheaper alternatives.
You looking to spent around £150.
Happy cleaning